Electric heater



Nov. 15, 1927. 1,649,421

J. SCHOENFELD ELECTRIC HEATER Filed Maron 25, 1925 4 sheets-sheet 1 J. SCHOENFELD ELECTRIC HEATER Filed March 23, 1925 4 Sheets-Sheet 2 Nov. 15;1927.

J. SCHOENFELD ELECTRIC HEATER Filed March 23, 1925 4 sheets-Sheet 5 J. SCHOE-NFELD ELECTRI C HEATE R Filed March 25, 1925 4 Sheets-Sheet 4 E M @vwl .Ml /1 Patented Nov. 15, 1927.

UNITED STATES .PATENT OFFICE.

JOSEPH SCHOENFELD, OF ALAMEDA, CALIFORNIA, ASSIGNOR TO THE MAGNAITOX COMPANY, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION F ARIZONA.

ELECTRIC HEATER.

Application med March 2s, 1925. serial No. 17,560.

This invention relates to electric heaters and especially to that type known as con- 4 vection heaters.

The object of the present invention 1s to generally improve and simplify the construction and operation of heaters ofthe characterdescribed; to provide a heater consisting of a plurality of casing sections adapted to be 'assembled in line formation 1o in a. manner similar to a sectional steam radiator, so that heaters of various sizes and capacities may be obtained; to pro-vide means for supporting one or more heating units within each casing section; to provide means whereby the casing sections may be quickly and readily interlocked and secured with relation to each other; to provide means whereby'an electrical connection is automatically formed between the heating units and the several casing sections when the casing sections are assembled and interlocked; and further, to provide a structure whereby circulation of air is increased ,and a comparatively cool exterior surface is obtaine One form which my invention may assume is exemplified in the following description and illustrated in the accompanying drawings, in which,

F ig. 1 is aside elevation of the electric heater;

Fig. Q is a partial side elevation of the electric heater, said side elevation being a central vertical longitudinal section; p

Fig. 3 is a transverse vertical section;

Fig. 4 is a plan view partially in section;

Fig. 5 is a bottom view;

Figj is a perspective view of the upper ends of a pair of casing sections;

Fig. 7 is a perspective View showing the electrical connections formed between the lower ends of aA pair of adjacent casing sections. 4

Referring to the drawings in detail and particularly to Fig. 1, A, B and C represent a plurality of casing sections which are assembledin line formation and interiorly of which are mounted a suitable number of electric heating units, which will hereinafter be described. Each casing section is provided with a base section, such as shown at 2, 3 and iIl respectively, and-the two base members shown at 2 and 4 are provided with supporting feet 5 which are attached to the :.5 base"- se'ctions,.as shown at 6 in Fig. 5. Disinafter be described.

The casing sections are divided into kend sections, such as shown at Aand' C, and

intermediate sections, such as indicated at B, there being only one intermediate section shown in this instance, but it should be understood that a number of intermediate sections may be employed if it is desired to increase the size orv capacity of the heater as a whole.y The end sections A and C are provided with handles 9 by which the heater may be lifted and carried from place to place, and one of the end sections is also provided with a. switch 10 which controls the circuits through the heating units.

The construction of the individual casing sections is perhaps 'best illustrated in igs. 4, 6 and 7. Fig. 6 showsthe upper ends of the end section A and the intermediate section B. The end section A consists of an end platell and a pair of side plates 12 and 13. The ends of the side plates 12 and 13, adjacent the intermediate section 4B,are turned inwardly as at 14 and the function of these inturned ends will later be described.` Secured to the side plates 12 and 13 are bracket members 15 and similarly secured to the end plate 11 is a bracket 16. Similar brackets 15 and 16 are secured to the lower ends of the end and side plates, thus providing a pair of brackets for each plate which are disposed at the upper and lower ends thereof. These brackets serve as supports for a pair of inner side plates 17and an inner end plate 18. The inner'ends of the side plates 17 are turned inwardly, as shown at 19, to assume a position in parallelism with the inturned ends 14 and a passage or intermediate space is thus formed between the such as indicated by the numerals 20. This intermediate passage is open at the bottom and is similarly open at the top. It forms asecondary air circulating passage, the function of'which will hereinafter vbe described.

The inturned ends 14 and 19are`provided for the purpose of reinforcing the ends of the side plates and to a certain extent to close the intermediate passage 20 where it adjoins the intermediate section B.y

plates 13-17, 12-17 and 11--18,

side The several side and end plates just de scribed and which form the casing of the end section A are, as previously stated, supported by a base sectiomsuch as shown at 2. This base section may be constructed of cast-iron or any other suitable materlal and the lower ends of the inner side and end lates are -provided with one or more foot ugs, such as shown at 22 in Fig. 7, which are secured to the 'base casting 2. By again referring to Fig. I it will be noted that the inner end and side plates do not extend downwardly asfar as the exterior end and plates. This is important; that is, the exterior end and side plates extend downwardl into contact'with the base member 2, while the inner end and side plates terminate at a point sufficiently above the same to permit air to enter and pass upwardly through the connected intermediate pas sa es 20.l ,y i

t will also he noted by referring to Fig. 6'that the upper ends of the' inner end and side plates project a. sli ht distance above the exterior end and si e plates and that the ornamental cover sections 7 are su ported by lugs 24, thus permitting the air rising upwardly through the intermediate passages 20to escape freely in under the cover and through `the openings formed therein.

The two end sections A and C are identical and the description of theconstruction of one should therefore suiiice. The construction of the intermediate section is slightly diierent and will therefore be described in detail; It consists of a pair of exterior side plates 25 and a pair of inner side plates 26, the ends of the exterior and interior side plates being anged or turned inwardly and outwardly respectively, as shown at 27 and 28, to reinforce and strengthen the same and also to substantially close a passage 29 formed between the same. There is a passage formed between each pair of side plates and there will accordingly be two passages 29 in the intermediate section. These-passages extend from end toend and are open at both the top and bottom to permit air to freely rise and escape when the heater is in operation, a free entrance of air being secured at the bottom by shortening the inner side plates, and a free-escape of air being insured at the top by shortening the exterior side plates.

The inner plates are secured with relation to the exterior plates by brackets 15 disposed at the upper and lower ends of the exterior side plates and a permanent spacing is thus maintained between the same. The inner side plates are in this instance also provided with lugs, such as shown at 24, to support the ornamental cover plate 7.

Both the intermediate and the end sections are provided with inwardly extending clips or arms, such as shown at 30, to which ,extend zigzag fas ion from the to heating elements are secured. The heating elements proper consist ofsa pair of interspaced' channel-bars 31 and 32 connected at their upper and lower ends by means of cross-bars 33. These cross-bars are riveted or otherwise secured to the members 30 and theyare thus rigidly secured within the respective casing sections. Each heating unit in reality consists of an elongated rectangular-shaped 'frame consisting of a pair of channe bars 32 and up er and lower crossbars 33. -The channel ars have s ools secured to their sides, as indicate These spools are-interspacedz as shown, and the heating element or resistance wire is wound from one spool to the other as shown at 35. The heatin elements in other words to the bottom of the respective casings an as such present a large area for the heating of air, as will hereinafter be described.

With a heatng consisting of three casing sectlons, as sh wn at A, B and C, it will be seen that there will be three intermediate air passages, such as shown at 20, in each end section and two intermediate air pas? sages, such as shown at 26, in the intermediate section. It will further be noted that as the several casing sections are assembled a large central common chamber will be formed in which are disposed heating elements. The base members 2, 3 and 4 are open so that air may freely enter the lar e common chamber containing the heating elments andso that it may also enter the intermediate passages previously described.

The air contacting with the heat resistance elements 35 will naturally rise, due to the heat absorbed, and as such will freely discharge through the openings in the ornamental cover plates 7 Heat will also be transmitted to the inner side and Jend plates by radiation, conduction and otherwise and the plates will thus assume a fairly high temperature. The heating of the inner side andl'nd plates will of course, induce an upward flow of air through the several intert mediate air passages described and this air will also discharge through the o enings in the ornamental cover plates an artially around the edges of the same, as the cover plates are supported in a slightly elevated position with relation to the uplper ends of the casing sections A, B and This induced flow of air materially increases the total volume of air heated, and it furthermore serves another important function, towit, that of maintaining the exterior side and end plates at a fairly low temperature or at least at a temperature which will prevent a child from being burnt if it should accidentally bump into the heater or otherwise touch the same.

The intermediate sectionis, of course, supported with relation to its base 3, by means bent from strips of metal, such as shown at 40 and 40, which are riveted or otherwise secured to the inner side and end plates. One end of each metal strip 40 is turned inwardly, as shown at 41, and one end of each metal strip a is bent to form a hook-shaped member 42 which is adapted to hook over the inturned ends 41. 4These inturned ends 41 and 42 form an interlock between the upper ends of the casing sections. Other means are. employed for interlocking and securing the lower ends of the casing sections and this is perhaps best illustrated in Fig. 5. This figure clearly illustrates that the several base sections are formed of independent castings and that they are interlocked or secured with relation to each other by means of left and right hand projecting lugs such as indicated at and 51 respectively. The lugs 50 are .formed on the end and intermediate casing sections respectively and so are-the lugs 51. This arrangement of the lugs permits right and left hand reversal when desired of the*` several casing sections, and as the lugs always overlap the adJacent sections no matter how disposed, itis obvious that it is' only necessary to insert screws, such as shown at 52, to secure the several base sections with relation to each other. The lower ends of the casing sections as already described are secured to their respective base .sections by means of the foot lugs 22 and 22a, and as the bases are interlocked with relation to each otherby means of the lugs 50 and 51, it is obvious that the casings will be rgidly secured both at their upper and lower ends.

The present invention involves another feature, to-wit, that of automatically establishing an electrical connection between the heating units disposed in the several casing sections when they areassembled and interlocked; The automatic electrical connection is perhaps best illustrated in Figs. 5 and 7, which illustrates the lower portion of the casing sections Apand B.

The opposite ends of the metal which form the foot lugs 22 of the tion A, are bent inwardly, and they support a cross-bar strips, casing secas shown at 54, 55. This crossbar carries a series of s ring fingers, such as shown at 56, on one si e and a plurality of terminal lugs 57 on the opposite' side, the

terminal lugs r57 and the spring fingers 56 being secured to the cross-bar by a common bolt or screw 58. The lingers and terminal lugs 57 are,` arranged 1n pairs, as shown. The .strip of metal from which the foot lugs 22*l are formed on thel intermediate section B carries a cross-bar 60. This crossbar forms a support for a plurality of knife contacts 61, which are formed integral with terminal lugs 62; that is, the knife contacts and terminal lugs are formed out o a single strip of-metal which'is bent U-shaped, as indicated at 63, so that it will straddle the cross-bar 60 and may be readily secured by screws 64. The knife contacts 61 enter between the resilient fingers 56 when the casing sections are assembled and an automatic electrical connection is thus established between the several heating units, as the heating units are in turn connected by wires, as

shown in Fig. 5, wit-h the terminal lugs 57 and 62. f

From the foregoing i-t can be seen that an electric heater of the convection type has been formed which consists of a pair of end sections A and C and one or more intermediate sections B. From the description of the interlocking mechanism employed, itd can now be readily understood that one or more intermediate sections may be inserted'between the end sections A and C if desired. It is thus possible to increase or decrease the size of the heater as desired without resorting to mechanical changes or complications. A large volume of air can be raised to a desired temperature by a heater of this char-- aoter as the air is maintained in constant circulation in an upward direction not only through .the main common central chamber formed between the several casing sections, but also through the`intermediate air passages provided. These passages serve two functions, not only that of increasing the volume of air circulated, but also that of maintaining the exterior side and end plates at a temperature so low that danger of accidental burning of children, or otherwise, is positively prevented. f

A simple mechanical interlock i's provided whereby three or more casing sections 'may` be quickly and 4substantially vassemblecill and anautomatic electrical:connect-ion is' atfthe" v lll the materials and finish of the several parts employed may be such as -the experience and judgment of the manufacturer may dictate or various uses may demand.

Having thus described my invention, what l claim and desire to secure by Letters Patent iS- l. A heater of the character described comprising a paii` of end casing sections and an intermedia-.te casing section, means whereby said casing sections may be interlocked and assembled as a unit, an inner casing section in each end and intermediate section, said inner sections forming a common central air passage and an intermediate air passage, and an electric heating unit in each casing section and. disposed in the common central passage, said central and intermediate passages being open at the top and bottom to permit an upward low of air therethrough. L 2. A heater of the character described comprising a pair of end casing sections and an intermediate casing section, means whereby said casing sections may be interlocked and assembled asa unit, an inner casing section in each end and intermediate section, said inner sections forming a central air passage common to all of the casing sections and also forming separated intermediate air passages in each casing section, and an elect-ric heating unit in each casing section and disposed in. the central passage, said central and intermediate passages being open at the top and bottom to permit an upward flow of air therethrough.

3. A heater of the character described comprising a pair of end casing sections and an intermediate casing, section, an electric .heating unit in each casing section, 'means permitting assembling and interlocking of the casing sections to form a unit, and means whereby an electric circuit connection is automatically formed between the heating units when the casing sections are assembled.

4. A heater of the character described comprising a pair of end casing sections and 4an intermediate casing section, an electric heating unit 1n each casing section, means permitting assembling and interlocking .of

, the casing sections to forma unit, and-rmeans cooperating therewith whereby an electric circuit connection is automatically formed between the heating units when the casing sections are'assembled.

5. A heater of 'the character described comprising a plurality of casing sections, an

electric' heat-ing element in each casin section, means whereby said casings may e interlocked as a uni-t, andmeans whereby an electric circuit Aconnection is automaticallyl established through the heating element when the casing sections are interlocked.

6. A heater of the-character described comprising a plurality of casing sections, an

electric heating element in each casing section, and means on each casing section whereby the casing sections may be assembled as a unit and'an electric circuit connection between the heating elements simultaneously established.

7. A heater of thel character described comprising a plurality of casing sections an electric heating element in eacheasing, electric contact terminals on each casing, and means on each casing section for securin the casing sections with relation to eac other and for bringing the electric contact terminals into. engagement with each other to form a circuit through the heating ele-' ments.

8. A heater of the character described comprising a plurality of casing sections, an electric heating element in each' casing, interlocking members on the upper ends of the casing sections whereby the casing sections iiiay ybe interlocked and connected, lugs on the lower ends of the casing sections adapted to overlap each other when the casing sections are assembled, and means for securing the overlapping lugs with relation to each other.

9. A heater of the character described comprising a plurality of casing sections, an electric heating element in each casing, interlocking members on the upper ends of the casing sections whereby the casing sections may be interlocked and connected, lugs on the lower ends of the casing sections adapted to overlap each other When the casing sections are assembled, means for securing the overla ping lugs with relation to each other, knifc shaped contact terminals in certain casing sections, and resilient contact terminals in the adjacent casing sections to' receive the knife shaped contacts, said contact terminals adapted to be brought into engagement with each other to form a circuit through the heating element when the casing sections are assembled.

10. Iny a sectional heater of the character described a plurality of assembled casin sections, said casing sections being elongated andvertically disposed and open `at their top and bottom ends, a heating element within each casing section to produce an upward flow of air, and a cover member for each section.

11. A heater of the character described vcomprising a plurality of casing sections which are adapted to be assembled, an electric heating unit .in each section, and means whereby an electric circuit connection is automatically formed through the heating unitswhen the sections are assembled.

l2'. A heater of the character described comprising a plurality of casing sections which are adapted to be assembled, an electric heating unit in each section, and contact members on each section which are brought into enEa-menttoiforrnja circuit connection and one endV Wall and said intermediate sec-l tion consisting of side walls only, and means for assembling the sections, said sections when assembled forming an interior chamber common to all the casing sections and open at the top and bottom, a heating'element in eachl casing section, an individual cover member supported in the upper end of each casing section.

14.' A heater f the character described comprising a pair of end casing sections, each section consisting of a pair of side walls and-one end wall, interspaced side wall members carried by each section, interspaced end `walls carried byA each section and forming mtermediate air passages, means for assembllng the two casing sections, said casing sections when assembled'forming an interior chamber commonl to all casing sections and an intermediate annular air chamber.

' 15. A heater ofthe character described comprising a pair of end casing sections and an intermediate casing section, said end sections each consisting of a pair of side walls and one end wall, and said intermediate section consisting of side walls only, meansfor assembling the sections, said sectionswhen assembled forming an interior chamber common to all of the 'casing sections, and interspaced plates secured to the side and end walls of the end sections and the side walls of the intermediate section and forming intermediate air passages.

JOSEPH SCHOENFELD. 

